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linux/fs/debugfs/file.c
Arnd Bergmann 6038f373a3 llseek: automatically add .llseek fop 
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time.  Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
//   but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
   *off = E
|
   *off += E
|
   func(..., off, ...)
|
   E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
  *off = E
|
  *off += E
|
  func(..., off, ...)
|
  E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
 ...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
 .llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
 .read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
 .write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
 .open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
...  .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
...  .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
...  .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+	.llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
 .write = write_f,
 .read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
2010-10-15 15:53:27 +02:00

537 lines
20 KiB
C
Raw Blame History

/*
* file.c - part of debugfs, a tiny little debug file system
*
* Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
* Copyright (C) 2004 IBM Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*
* debugfs is for people to use instead of /proc or /sys.
* See Documentation/DocBook/filesystems for more details.
*
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/namei.h>
#include <linux/debugfs.h>
static ssize_t default_read_file(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
return 0;
}
static ssize_t default_write_file(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
return count;
}
static int default_open(struct inode *inode, struct file *file)
{
if (inode->i_private)
file->private_data = inode->i_private;
return 0;
}
const struct file_operations debugfs_file_operations = {
.read = default_read_file,
.write = default_write_file,
.open = default_open,
.llseek = noop_llseek,
};
static void *debugfs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
nd_set_link(nd, dentry->d_inode->i_private);
return NULL;
}
const struct inode_operations debugfs_link_operations = {
.readlink = generic_readlink,
.follow_link = debugfs_follow_link,
};
static int debugfs_u8_set(void *data, u64 val)
{
*(u8 *)data = val;
return 0;
}
static int debugfs_u8_get(void *data, u64 *val)
{
*val = *(u8 *)data;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
/**
* debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
* @name: a pointer to a string containing the name of the file to create.
* @mode: the permission that the file should have
* @parent: a pointer to the parent dentry for this file. This should be a
* directory dentry if set. If this parameter is %NULL, then the
* file will be created in the root of the debugfs filesystem.
* @value: a pointer to the variable that the file should read to and write
* from.
*
* This function creates a file in debugfs with the given name that
* contains the value of the variable @value. If the @mode variable is so
* set, it can be read from, and written to.
*
* This function will return a pointer to a dentry if it succeeds. This
* pointer must be passed to the debugfs_remove() function when the file is
* to be removed (no automatic cleanup happens if your module is unloaded,
* you are responsible here.) If an error occurs, %NULL will be returned.
*
* If debugfs is not enabled in the kernel, the value -%ENODEV will be
* returned. It is not wise to check for this value, but rather, check for
* %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
* code.
*/
struct dentry *debugfs_create_u8(const char *name, mode_t mode,
struct dentry *parent, u8 *value)
{
/* if there are no write bits set, make read only */
if (!(mode & S_IWUGO))
return debugfs_create_file(name, mode, parent, value, &fops_u8_ro);
/* if there are no read bits set, make write only */
if (!(mode & S_IRUGO))
return debugfs_create_file(name, mode, parent, value, &fops_u8_wo);
return debugfs_create_file(name, mode, parent, value, &fops_u8);
}
EXPORT_SYMBOL_GPL(debugfs_create_u8);
static int debugfs_u16_set(void *data, u64 val)
{
*(u16 *)data = val;
return 0;
}
static int debugfs_u16_get(void *data, u64 *val)
{
*val = *(u16 *)data;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
/**
* debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
* @name: a pointer to a string containing the name of the file to create.
* @mode: the permission that the file should have
* @parent: a pointer to the parent dentry for this file. This should be a
* directory dentry if set. If this parameter is %NULL, then the
* file will be created in the root of the debugfs filesystem.
* @value: a pointer to the variable that the file should read to and write
* from.
*
* This function creates a file in debugfs with the given name that
* contains the value of the variable @value. If the @mode variable is so
* set, it can be read from, and written to.
*
* This function will return a pointer to a dentry if it succeeds. This
* pointer must be passed to the debugfs_remove() function when the file is
* to be removed (no automatic cleanup happens if your module is unloaded,
* you are responsible here.) If an error occurs, %NULL will be returned.
*
* If debugfs is not enabled in the kernel, the value -%ENODEV will be
* returned. It is not wise to check for this value, but rather, check for
* %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
* code.
*/
struct dentry *debugfs_create_u16(const char *name, mode_t mode,
struct dentry *parent, u16 *value)
{
/* if there are no write bits set, make read only */
if (!(mode & S_IWUGO))
return debugfs_create_file(name, mode, parent, value, &fops_u16_ro);
/* if there are no read bits set, make write only */
if (!(mode & S_IRUGO))
return debugfs_create_file(name, mode, parent, value, &fops_u16_wo);
return debugfs_create_file(name, mode, parent, value, &fops_u16);
}
EXPORT_SYMBOL_GPL(debugfs_create_u16);
static int debugfs_u32_set(void *data, u64 val)
{
*(u32 *)data = val;
return 0;
}
static int debugfs_u32_get(void *data, u64 *val)
{
*val = *(u32 *)data;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
/**
* debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
* @name: a pointer to a string containing the name of the file to create.
* @mode: the permission that the file should have
* @parent: a pointer to the parent dentry for this file. This should be a
* directory dentry if set. If this parameter is %NULL, then the
* file will be created in the root of the debugfs filesystem.
* @value: a pointer to the variable that the file should read to and write
* from.
*
* This function creates a file in debugfs with the given name that
* contains the value of the variable @value. If the @mode variable is so
* set, it can be read from, and written to.
*
* This function will return a pointer to a dentry if it succeeds. This
* pointer must be passed to the debugfs_remove() function when the file is
* to be removed (no automatic cleanup happens if your module is unloaded,
* you are responsible here.) If an error occurs, %NULL will be returned.
*
* If debugfs is not enabled in the kernel, the value -%ENODEV will be
* returned. It is not wise to check for this value, but rather, check for
* %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
* code.
*/
struct dentry *debugfs_create_u32(const char *name, mode_t mode,
struct dentry *parent, u32 *value)
{
/* if there are no write bits set, make read only */
if (!(mode & S_IWUGO))
return debugfs_create_file(name, mode, parent, value, &fops_u32_ro);
/* if there are no read bits set, make write only */
if (!(mode & S_IRUGO))
return debugfs_create_file(name, mode, parent, value, &fops_u32_wo);
return debugfs_create_file(name, mode, parent, value, &fops_u32);
}
EXPORT_SYMBOL_GPL(debugfs_create_u32);
static int debugfs_u64_set(void *data, u64 val)
{
*(u64 *)data = val;
return 0;
}
static int debugfs_u64_get(void *data, u64 *val)
{
*val = *(u64 *)data;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
/**
* debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
* @name: a pointer to a string containing the name of the file to create.
* @mode: the permission that the file should have
* @parent: a pointer to the parent dentry for this file. This should be a
* directory dentry if set. If this parameter is %NULL, then the
* file will be created in the root of the debugfs filesystem.
* @value: a pointer to the variable that the file should read to and write
* from.
*
* This function creates a file in debugfs with the given name that
* contains the value of the variable @value. If the @mode variable is so
* set, it can be read from, and written to.
*
* This function will return a pointer to a dentry if it succeeds. This
* pointer must be passed to the debugfs_remove() function when the file is
* to be removed (no automatic cleanup happens if your module is unloaded,
* you are responsible here.) If an error occurs, %NULL will be returned.
*
* If debugfs is not enabled in the kernel, the value -%ENODEV will be
* returned. It is not wise to check for this value, but rather, check for
* %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
* code.
*/
struct dentry *debugfs_create_u64(const char *name, mode_t mode,
struct dentry *parent, u64 *value)
{
/* if there are no write bits set, make read only */
if (!(mode & S_IWUGO))
return debugfs_create_file(name, mode, parent, value, &fops_u64_ro);
/* if there are no read bits set, make write only */
if (!(mode & S_IRUGO))
return debugfs_create_file(name, mode, parent, value, &fops_u64_wo);
return debugfs_create_file(name, mode, parent, value, &fops_u64);
}
EXPORT_SYMBOL_GPL(debugfs_create_u64);
DEFINE_SIMPLE_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set, "0x%04llx\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set, "0x%08llx\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
DEFINE_SIMPLE_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set, "0x%016llx\n");
/*
* debugfs_create_x{8,16,32,64} - create a debugfs file that is used to read and write an unsigned {8,16,32,64}-bit value
*
* These functions are exactly the same as the above functions (but use a hex
* output for the decimal challenged). For details look at the above unsigned
* decimal functions.
*/
/**
* debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
* @name: a pointer to a string containing the name of the file to create.
* @mode: the permission that the file should have
* @parent: a pointer to the parent dentry for this file. This should be a
* directory dentry if set. If this parameter is %NULL, then the
* file will be created in the root of the debugfs filesystem.
* @value: a pointer to the variable that the file should read to and write
* from.
*/
struct dentry *debugfs_create_x8(const char *name, mode_t mode,
struct dentry *parent, u8 *value)
{
/* if there are no write bits set, make read only */
if (!(mode & S_IWUGO))
return debugfs_create_file(name, mode, parent, value, &fops_x8_ro);
/* if there are no read bits set, make write only */
if (!(mode & S_IRUGO))
return debugfs_create_file(name, mode, parent, value, &fops_x8_wo);
return debugfs_create_file(name, mode, parent, value, &fops_x8);
}
EXPORT_SYMBOL_GPL(debugfs_create_x8);
/**
* debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
* @name: a pointer to a string containing the name of the file to create.
* @mode: the permission that the file should have
* @parent: a pointer to the parent dentry for this file. This should be a
* directory dentry if set. If this parameter is %NULL, then the
* file will be created in the root of the debugfs filesystem.
* @value: a pointer to the variable that the file should read to and write
* from.
*/
struct dentry *debugfs_create_x16(const char *name, mode_t mode,
struct dentry *parent, u16 *value)
{
/* if there are no write bits set, make read only */
if (!(mode & S_IWUGO))
return debugfs_create_file(name, mode, parent, value, &fops_x16_ro);
/* if there are no read bits set, make write only */
if (!(mode & S_IRUGO))
return debugfs_create_file(name, mode, parent, value, &fops_x16_wo);
return debugfs_create_file(name, mode, parent, value, &fops_x16);
}
EXPORT_SYMBOL_GPL(debugfs_create_x16);
/**
* debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
* @name: a pointer to a string containing the name of the file to create.
* @mode: the permission that the file should have
* @parent: a pointer to the parent dentry for this file. This should be a
* directory dentry if set. If this parameter is %NULL, then the
* file will be created in the root of the debugfs filesystem.
* @value: a pointer to the variable that the file should read to and write
* from.
*/
struct dentry *debugfs_create_x32(const char *name, mode_t mode,
struct dentry *parent, u32 *value)
{
/* if there are no write bits set, make read only */
if (!(mode & S_IWUGO))
return debugfs_create_file(name, mode, parent, value, &fops_x32_ro);
/* if there are no read bits set, make write only */
if (!(mode & S_IRUGO))
return debugfs_create_file(name, mode, parent, value, &fops_x32_wo);
return debugfs_create_file(name, mode, parent, value, &fops_x32);
}
EXPORT_SYMBOL_GPL(debugfs_create_x32);
/**
* debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
* @name: a pointer to a string containing the name of the file to create.
* @mode: the permission that the file should have
* @parent: a pointer to the parent dentry for this file. This should be a
* directory dentry if set. If this parameter is %NULL, then the
* file will be created in the root of the debugfs filesystem.
* @value: a pointer to the variable that the file should read to and write
* from.
*/
struct dentry *debugfs_create_x64(const char *name, mode_t mode,
struct dentry *parent, u64 *value)
{
return debugfs_create_file(name, mode, parent, value, &fops_x64);
}
EXPORT_SYMBOL_GPL(debugfs_create_x64);
static int debugfs_size_t_set(void *data, u64 val)
{
*(size_t *)data = val;
return 0;
}
static int debugfs_size_t_get(void *data, u64 *val)
{
*val = *(size_t *)data;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
"%llu\n"); /* %llu and %zu are more or less the same */
/**
* debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
* @name: a pointer to a string containing the name of the file to create.
* @mode: the permission that the file should have
* @parent: a pointer to the parent dentry for this file. This should be a
* directory dentry if set. If this parameter is %NULL, then the
* file will be created in the root of the debugfs filesystem.
* @value: a pointer to the variable that the file should read to and write
* from.
*/
struct dentry *debugfs_create_size_t(const char *name, mode_t mode,
struct dentry *parent, size_t *value)
{
return debugfs_create_file(name, mode, parent, value, &fops_size_t);
}
EXPORT_SYMBOL_GPL(debugfs_create_size_t);
static ssize_t read_file_bool(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
char buf[3];
u32 *val = file->private_data;
if (*val)
buf[0] = 'Y';
else
buf[0] = 'N';
buf[1] = '\n';
buf[2] = 0x00;
return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
}
static ssize_t write_file_bool(struct file *file, const char __user *user_buf,
size_t count, loff_t *ppos)
{
char buf[32];
int buf_size;
u32 *val = file->private_data;
buf_size = min(count, (sizeof(buf)-1));
if (copy_from_user(buf, user_buf, buf_size))
return -EFAULT;
switch (buf[0]) {
case 'y':
case 'Y':
case '1':
*val = 1;
break;
case 'n':
case 'N':
case '0':
*val = 0;
break;
}
return count;
}
static const struct file_operations fops_bool = {
.read = read_file_bool,
.write = write_file_bool,
.open = default_open,
.llseek = default_llseek,
};
/**
* debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
* @name: a pointer to a string containing the name of the file to create.
* @mode: the permission that the file should have
* @parent: a pointer to the parent dentry for this file. This should be a
* directory dentry if set. If this parameter is %NULL, then the
* file will be created in the root of the debugfs filesystem.
* @value: a pointer to the variable that the file should read to and write
* from.
*
* This function creates a file in debugfs with the given name that
* contains the value of the variable @value. If the @mode variable is so
* set, it can be read from, and written to.
*
* This function will return a pointer to a dentry if it succeeds. This
* pointer must be passed to the debugfs_remove() function when the file is
* to be removed (no automatic cleanup happens if your module is unloaded,
* you are responsible here.) If an error occurs, %NULL will be returned.
*
* If debugfs is not enabled in the kernel, the value -%ENODEV will be
* returned. It is not wise to check for this value, but rather, check for
* %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
* code.
*/
struct dentry *debugfs_create_bool(const char *name, mode_t mode,
struct dentry *parent, u32 *value)
{
return debugfs_create_file(name, mode, parent, value, &fops_bool);
}
EXPORT_SYMBOL_GPL(debugfs_create_bool);
static ssize_t read_file_blob(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
struct debugfs_blob_wrapper *blob = file->private_data;
return simple_read_from_buffer(user_buf, count, ppos, blob->data,
blob->size);
}
static const struct file_operations fops_blob = {
.read = read_file_blob,
.open = default_open,
.llseek = default_llseek,
};
/**
* debugfs_create_blob - create a debugfs file that is used to read a binary blob
* @name: a pointer to a string containing the name of the file to create.
* @mode: the permission that the file should have
* @parent: a pointer to the parent dentry for this file. This should be a
* directory dentry if set. If this parameter is %NULL, then the
* file will be created in the root of the debugfs filesystem.
* @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
* to the blob data and the size of the data.
*
* This function creates a file in debugfs with the given name that exports
* @blob->data as a binary blob. If the @mode variable is so set it can be
* read from. Writing is not supported.
*
* This function will return a pointer to a dentry if it succeeds. This
* pointer must be passed to the debugfs_remove() function when the file is
* to be removed (no automatic cleanup happens if your module is unloaded,
* you are responsible here.) If an error occurs, %NULL will be returned.
*
* If debugfs is not enabled in the kernel, the value -%ENODEV will be
* returned. It is not wise to check for this value, but rather, check for
* %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
* code.
*/
struct dentry *debugfs_create_blob(const char *name, mode_t mode,
struct dentry *parent,
struct debugfs_blob_wrapper *blob)
{
return debugfs_create_file(name, mode, parent, blob, &fops_blob);
}
EXPORT_SYMBOL_GPL(debugfs_create_blob);
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